Basic esters of cholanic and ketocholanic acids



Patented July 31, 1951 BASIC ESTERS F CHOLANIC AND KETOCHOLANIC ACIDS Robert R. Burtner, Skokie, 111., assignor to G. Searle & 00., Chicago, 111., a corporation of Illinois No Drawing. Application March 4, 1949, 7

Serial No. 79,731

' 14 Claims.

This invention relates to basic esters of cholanic and ketocholanic acids, to salts thereof and to the production of such esters. More particularly this invention relates to esters of the following general structural formula wherein there are not more than two keto groups in the cholanic acid moiety, and wherein Z is a lower alkylene radical and B is an aliphatic-type amino group.

This application is a continuation-in-part of my copending application Serial No. 622,081, filed October 12, 1945.

In the compounds of the foregoing type Z represents a lower alkylene radical, such as ethylene, propylene, 1,3-butylene, 2,3-butylene, or 1,2-butylene, amylene and related bivalent radicals derived from the saturated aliphatic hydrocarbons containing two to five carbon atoms. The amino radical B represents aliphatic-type amino radicals derived from primary and secondary organic amines having ionization constants in the range of 10- to 10- B therefore includes monalkylamino radicals and dialkylamino radicals wherein the alkyl groups may be the same or difierent and may contain from one to six carbon atoms. B also includes aliphatic-type cyclic amino radicals such as piperidino, pyrrolidino, morpholino, land thiamorpholino, as well as alkyl derivatives of such cyclic amino radicals, including 2-methylpiperidino, Z-methylpyrrolidino, 2-ethylpiperidino, 2- methylmorpholino, lupetidino and the like.

These esters may be obtained as viscous oils or glassy masses which are insoluble in water but readily soluble in a variety of organic solvents, or these oily or glassy'basic esters may be converted into salts, which are generally crystalline, by neutralization with an equivalent quantityjof any convenient non-toxic organic or inorganic acid. Among such acids are hydrochloric, hydrobromic, sulfuric, sulphamic phosphoric, boric, tartaric, citric, cinnamic, ascorbic, lactic, maleic, acetic, malic, succinic and the like. Salts are in generalsoluble in water and since they manifest all of the advantages of the esters as disclosed herein, they: constitute a preferred form for preparing and using these compounds. Though I have found the hydrochloride salts convenient to prepare and use, it will be understood that other salts may be employed and that the esters described in the appended claims may be in the form of the free base or any of its salts.

The cholanic and ketocholanic acids from which these esters are produced are well known in the prior art. Certain of the keto acids may be isolated from mammalian bile or may be prepared from the corresponding hydroxy cholanic acids by oxidation. Cholanic acid can be obtained by dehydration of the bile acids, followed by catalytic hydrogenation. Y

The esters of this invention and their salts are conveniently prepared by heating a mixture of the acid with an aminoalkyl halide in an organic solvent, such as isopropanol, acetone, methyl ethyl ketone, and the like. During this reaction the hydrohalide salt of the basic ester is formed. In certain instances this is obtained as a crystalline precipitate and may be ready isolated and purified. In the cases where the ester salt is not a crystalline precipitate it may be isolated by evaporation of the solvent, extraction of the residue with acid, neutralization of the acid extract, extraction with an organic solvent such as benzene, and then evaporation of the solvent to afford the basic ester. These basic esters may be converted to acid salts by treatment with an acid of the type discussed hereinabove and may be converted to quaternary ammonium salts by reaction with a reactive ester such as an alkyl halide or sulfate.

The products of this invention are useful as medicinal agents. They have favorable effects on fibrositis and certain types or arthritis. Certain of them appear to produce a synergistic effect when administered with vaccines. The compounds furthermore are useful as spasmolytic agents for relaxing smooth muscle tissue in general. Generally speaking, they are capable of relaxing smooth muscle spasms either neurotropic or musculotropic in origin. They appear to be effective in various kinds of smooth muscle, as typified conveniently by intestinal and uterine strips. The potency of the individual compounds of this invention naturally varies from one to another, but the more potent species approach in quantitative. activity the levels reported for some of the widely used natural and synthetic spasmolytic agents. For example, diethylaminoethyl dehydrodesoxytissue in general.

testinal strips caused by barium ions (considered to be typical of musculotropic spasms), It is but slightly less potent than the same reference compound in relaxing intestinalspasms induced by acetylcholine (considered to be typical of neurotropic spasms). toneal adminstration (in mice) is about the same as the reference compound, but'it is appreciably less toxic on oral administration. Likewise diethylaminoethyl desoxycholate hydrochloride is but a little less potent than the corresponding dehydrodesoxycholate as described above; though it is slightly more toxic than that compound.

As shown above, these compounds are useful as spasmolytic agents for relaxing smooth muscle However, the compounds of this invention are unique among all spasmolytic agents in that they possess the bile acid structure as the major portion of their molecule. It is well known that bile acids and their common derivatives are selectively secreted and concentrated into the bile. 'Qonsequently, the compounds described and claimed herein are of peculiar and unique interest in spastic states involving the gall bladder and other structures 1 through which bile is secreted and passed.

My invention is disclosed in detail by the following examples which are provided solely for the purpose of illustration and which are in no way intended to limit the invention in spirit and in scope.

- Ero l To a or .3 rams of dehyd i w holi eto hole iw acid i c i enti:

Its toxicity on intraperi-' me ers of warm is oo nol are added 7 g. of

fl-di thyl miooetb l chloride The mixt re i l x d or 1 9 55 and then str ped o olvent d r eouom- The i cous. re i ue is poured 1 er o 4% sodium h drox de solut on- The basic e er w ich e arates is extrac ed wi h be ze Th ben ene extra t i washe with Water, d i d nd Partia l e a rate Th hon: e o so uti rem in i fi e ed and hen treated wi h n, equi alent anh r u h roe hl r o n abso ute e ool l- The ec pitat of fi-diethylaminoethyl dehydrolithocholate is removed. washed with benzene, and dried in cu t can e uri e y c l zation. from methyl ethyl ketone. The salt thus ob tain'ed is moderately soluble in water.

Example 2 217 grams of dehydrodesoxycholic (3,l2 -diketo,-. cholanic) acid and 81.3 g. of p-diethylaminoethyl chloride are refluxed together in 660 cc. of isopropanol, and the oily ester base precipitated from Water and extracted with benzene as described in Example 1. Much of the benzene is removed from the extract by distillation, and a solution containing one equivalent of hydrogen chloride in anhydrous ethanol is added. The resulting solution is cooled and poured slowly into 4750 cc. of ether during vigorous stirring. The precipitate soon granulates, and is filtered,

washed with fresh ether, and dried in a vacuum.

over sodium hydroxide. The p-diethylaminoethyl dehydrodesoxycholate hydrochloride thus obtained may be purified by crystallization from methyl ethyl ketone, and when so purified melts at approximately 187 centigrade. It is readily soluble in water and alcohol, and sufficiently hygroscopic to render determinationflcf the melting point uncertain.

Operating in a similar manner, the fi-piperidinoethyl, p-dimethylaminoethyl, fi-diethylaminopropyl and 'y-diethylaminopropyl esters of dehydrodesoxycholic acid may be obtained as bydrochlorldes which are similarly hygroscopic, readily soluble in water, and frequently diflicult to crystallize satisfactorily.

Example 3 A warm solution of 38.9 g. of dehydrodesoxycholic acid in 150 cc. of isopropanol is refluxed for 3 hours with 12 g. of B-dimethylaminoethyl chloride. The solvent is then removed in vacuum and the residue poured into 2 liters of 0.5% sodium hydroxide solution. The aqueous suspension is extracted thoroughly with benzene. The benzene extract is washed with water and dried. It is filtered and then treated with a small excess of anhydrous hydrogen chloride in absolute alcohol. The mixture is diluted with dry ether and chilled. The precipitate of fi-dimethylaminoethyl dehydrodesoxycholate hydrochloride is removed and dried in vacuum. It is readily soluble in water and in alcohol.

Example 4 hydrodesoxycholate and its hydrochloride Example, 5

A solution of- 19.4 g. of dehydrodesoxycholic acid in '70 cc. of hot isopropanol is refluxed for 3 hours with 8 g. of fi-diethylaminopropyl chloride. The basic ester is isolated by benzene extraction as in Example 3'. It may be obtained from the benzene extract by evaporation in vacuum. It is a viscous oily material which is readily soluble in dilute hydrochloric acid.

Example? 25.3 g. dehydrohyodesoxycholic (3,6-diketocholanic) acid and 9.6 g. of fi-diethylaminoethyl chloride in 80 cc. of warm isopropanol are refiuxed for 3 hours. The hot'solution is filtered and then evaporated under vacuum. The residue is treated with 500 cc. of, 1% sodium hydroxide solution to precipitate the basic ester. The mix ture is extracted thrice with cc. portions of benzene and the combined extracts are washed wi h Wate a d d 0 c f e ene a e. removed by distillation and the residual benzene white crystals. A melting point could not be determined due to hygroscopicity. By drying at 100 C. and 0.5 mm. pressure, the anhydrous salt may be obtained.

Example 8 A solution of 19.4 g. of dehydrohyodesoxycholic acid and g. of fl-dibutylaminoethyl chloride in 70 cc. of hot isopropanol is refluxed for 3 hours. The solvent is then removed by evaporation under vacuum and the viscous residue of crude fi-dibutylaminoethyl dehydrohyodesoxycholate hydrochloride is dissolved in 1% hydrochloric acid and the resulting solution is filtered and then made alkaline. B-Dibutylaminoethyl dehydrohyodesoxycholate is separated from the aqueous solution by extraction with benzene. The benzene solution is washed with water and dried. On evaporation under vacuum there is obtained 5 dibutylaminoethyl dehydrohyodesoxycholate. which is a light colored oil which is solublein dilute hydrochloric acid.

Example 9 g, of dehydrodesoxycholic acid and 8 g. of fl-morpholinoethyl chloride are reacted in 80 cc. of isopropanol by the method of Example 3. The organic base is isolated by the procedure of Example 8. fi-Morpholinoethyl dehydrodesoxycholate is a light colored oil which is soluble in dilute hydrochloric acid.

Ewample 10 stituent is selected from the group consisting of di(lower alkyl) amino, piperidino, pyrrolidino and niorpholino radicals.

2. As a new composition of matter, an acid addition salt of a di(lower alkyDamino-loweralkyl ester of a cholanic acid which contains not more than two keto substituents and which is devoid of hydroxyl substituents.

3. As new compositions of matter, acid addition salts of a di(lower-alkyl) amino-lower-alkyl ester of dehydrodesoxycholic acid.

4. As new compositions of matter, lsaid addition salts of a di(lower-alkyl)aminoethyl ester of dehydrodesoxycholic acid.

5. As new compositions of matter, acid addition salts of ,B-diethylaminoethyl dehydrodesoxycholate.

A suspension of 1.94 g. of dehydrochenodesoxy- I cholic (3,7-diketocholanic) acid in 10 cc. of warm isopropanol is refluxed for 3 hours with 0.68 g. B-diethylaminoethyl chloride. The solvent is stripped oil under vacuum and the viscous residue of crude p-diethylaminoethyl dehydrochenodesoxycholate is agitated with a cold solution of 0.5% sodium hydroxide. The alkaline suspension is extracted with benzene and the benzene extract is washed with water and dried. The benzene is removed under vacuum and B- diethylaminoethyl dehydrochenodesoxycholate is isolated as a light-colored viscous oil.

I claim: I

1. As a new composition of matter, an aminolower-alkyl ester of a cholanic acid which contains not more than two keto substituents and which is devoid of hydroxyl substituents, and acid addition salts thereof, wherein the amino sub- 6. p-Diethylaminoethyl dehydrodesoxycholate hydrochloride.

7. As a new composition of matter, an acid addition salt of a piperidino-lower-alkyl ester of a cholanic acid which contains not more than two keto substituents and which is devoid of hydroxyl substituents.

8. As a new composition of matter, an acid addition salt of a morpholino-lower-alkyl ester of a cholanic acid which contains not more than two keto substituents and which is devoid of hydroxyl substituents.

9. As new compositions of matter, acid addition salts of B-piperidinoethyl dehydrodesoxycholate.

10. p-Piperidinoethyl dehydrodesoxycholate hydrochloride.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,677,554 Gams et a1. July 17, 1928 1,933,003 Boedecker Oct. 31, 1933 2,023,075 Harris Dec. 3, 1935 2,296,677 Kussner Sept. 22, 1942 2,313,016 Horenstein et al. Mar. 2, 1943 2,337,563 Macker Dec. 28, 1943 2,456,363 Bergel et a1. Dec. 14, 1948 Certificate of Correction Patent No. 2,562,351 July 31, 1951 ROBERT R. BUR-TNER It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 2, line 24, for ready read readily; line 39, for types or read types of; column 3, line 3, for fluoro-Q-carboxylate read fluorene-Q-carboarylate; column 6, line 12, for said read acid;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oifice. Signed and sealed this 25th day of December, A. D. 1951.

[sun] THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

1. AS A NEW COMPOSITION OF MATTER, AN AMINOLOWER-ALKYL ESTER OF A CHOLANIC ACID WHICH CONTAINS NOT MORE THAN TWO KETO SUBSTITUENTS AND WHICH IS DEVOID OF HYDROXYL SUBSTITUENTS, AND ACID ADDITION SALTS THEREOF, WHEREIN THE AMINO SUBSTITUENT IS SELECTED FROM THE GROUP CONSISTING OF DI(LOWER ALKYL) AMINO, PIPERIDINO, PYRROLIDINO AND MORPHOLINO RADICALS. 